The present invention is directed to switching devices coupling an output locus with one of a first voltage source and a second voltage source, and especially to switching devices embodied in a charge pump devices.
A typical prior art charge pump device relies on voltage feedback that controls frequency of an oscillator unit, such as a voltage controlled oscillator (VCO) unit. Problems are experienced using such circuitry in that frequency variation limits output current range of the VCO unit which limits the regulating capability of the charge pump device. Further, voltage spikes are commonly generated using such circuitry; those voltage spikes have amplitudes that are inversely proportional to the frequency of the voltage feedback signal. The amplitudes of the voltage spikes vary significantly with the load current applied to the charge pump device, resulting in an unstable arrangement.
Another prior art charge pump device is a regulator-based charge pump device that relies on an input voltage being regulated by a pre-regulator unit. This configuration dissipates significant power and occupies increased chip area over a VCO controlled configuration, both of which characteristics are disadvantageous in today's market where smaller more compact products are desired.
There is a need for an apparatus and method for regulating a switching device that reduces limitations for load current range for frequency regulated switching devices, such as frequency regulated charge pumps.
There is a need for an apparatus and method for regulating a switching device that required less power and less chip area than prior art regulator-based regulated switching devices.